Dielectric fluids, e.g., refrigerants, dry-cleaning solvents, and other non-aqueous based solutions, are frequently employed to clean high technology instruments and devices, including, for example, sensitive electronics and/or electrical equipment. Conventional cleaning methods may include, for the purpose of illustration and not limitation, immersing, rinsing, spraying, vaporizing, and so forth. Disadvantageously, during repeated use in cleaning operations, dielectric fluids may become contaminated, e.g., by particles, impurities, solid substances, liquid substances, and the like.
Exemplary sources of impurities/contaminants can include printed circuit board (PCB) fluxes, plasticizers, water, and so forth. Fluxes, e.g., resin and rosin, may originally be found on the PCB but can be washed from the PCB by dielectric fluids. Typical fluxes have boiling points that may vary between about 100° C. and about 130° C. Plasticizers include additives used to improve, for example, the softness of the plastic typically found in the coatings of some electrical cables. As with fluxes, dielectric fluid washes out the plasticizers, which then remain suspended or in solution in the dielectric fluid. Due to the repeated heating and cooling of electronic equipment, water vapor in the ambient air can condense and subsequently dissolve into the dielectric fluid.
As a result of this contamination, the dielectric fluid may become less effective as a cleaning agent. In particular, repeated use of the dielectric fluid may affect the fluid's electrical resistivity, which is a measure of the fluid's resistance to the transmission of electricity, which might be harmful to the electronics and/or electrical equipment.
A recent implementation of dielectric fluids as a cleaning agent involves immersion cooling of electronic equipment, especially for single-phase or two-phase liquid cooling of electronics or other electrical items. When used repeatedly in immersion cooling, the electrical resistivity, the optical transmittance, and other properties of the dielectric fluid may be deleteriously affected. Hence, in order to ensure that the working dielectric fluid is maintained in or proximate its pure form or pure state, the dielectric fluid should remain extremely clean and essentially free of liquid and/or solid contaminants, such that electrical resistivity, optical transmittance, and other properties of the dielectric fluid remain within acceptable limits.
The high cost of some dielectric fluids suggests there may be advantages of recovery, recycling, and re-use of dielectric fluids being used, for example, in immersion cooling. However, any recovery and re-use necessitates the removal or separation of a myriad of solid and liquid contaminants from the dielectric fluid. Exemplary contaminants, for the purpose of illustration and not limitation, may include fine- to coarse-grained solid particles, liquid contaminants that do not dissolve in the dielectric fluid, liquid contaminants that partially dissolve in the dielectric fluid, and liquid contaminants that dissolve fully in the dielectric fluid. Disadvantageously, dissolved and partially dissolved liquid contaminants may form an azeotrope, making removal and separation from the dielectric fluid, e.g., by distillation, more difficult due to the common or proximate boiling points of the liquids in the azeotrope mixture.
The related art provides exemplary systems and methods for filtering and/or heating a fluid containing undesirable contaminants. However, some of these systems and methods typically cannot effectively filter and remove dissolved and/or miscible fluids.